Phosphorescent material is commonly employed as a passive light source to provide light when a primary source of light (e.g., an electrically powered light source and/or sunlight) is unavailable. When primary light is being supplied to a viewing environment by the primary light source, the phosphorescent material absorbs this primary light and then emits the absorbed light in the absence or minimization of the primary light. Thus, the phosphorescent material can provide light in an emergency situation without batteries and/or on-premise generators being employed. For this reason, phosphorescent material will often be used to make emergency information signs, which must convey emergency indicia (e.g., the word “EXIT” or an arrow pointing in an appropriate escape direction) in dark conditions.